Colouring materials, such as pigment granules, have been used to produce concrete and concrete paving of particular colours. The coloured concrete or paving is prepared by adding the colouring material, such as pigment granules, to the mixture used to prepare the concrete or paving. The mixture is then poured and cured to form the coloured concrete or paving. In this process, the colouring materials must be added during the preparation of the concrete or paving. Accordingly, this process cannot be used to change the colour of the concrete or paving once the concrete or paving has been prepared. Replacing an existing concrete or paved surface with a new concrete or paved surface of a different colour can be an expensive and time-consuming activity.
One way of colouring the surface of various building materials such as an existing concrete surface has been to paint the surface with conventional paint compositions. However, this results in a surface having different appearance and texture to the original surface. Further, due to exposure to the elements (e.g. sunlight, rain, etc) and wear (e.g. a surface which is driven on or walked on), over time, the paint on the surface fades, cracks and/or peels giving a very undesirable appearance.
It would therefore be advantageous to provide an alternative composition and method for colouring the surface of a porous substrate.